#include<stdio.h>
int main()
{
	int c;
	printf("please input grades:");
	scanf("%d",&c);
  	if(c<60)
 	printf("the level is E.");
	else if(c<70&&c>=60)
	printf("the level is D.");
 	else if(c<80&&c>=70)
 	printf("the level is C.");
 	else if(c<90&&c>=80)
 	printf("the level is B.");
 	else if(c<100&&c>=90)
 	printf("the level is A.");
 	else if(c=100)
 	printf("perfect!");
 	return 0;
 	
}
